I think that's a good thing for you to do Ruthanne, and especially if you are getting to know someone who is like this. It's certainly a changing world that we live in isn't it? We keep learning and understanding things continually and we become more accepting of differences through that.
I once watched a short documentary about a doctor in Europe who was researching about transgender people and he came to the conclusion that transgendered brains are actually different then the brains of the rest of us. Through examining the brain tissue, he could see that the part that controls sexuality is actually different in them. I can't remember whether it was bigger, different shaped or structured or what (it was a number of years ago that I saw it), but yes, not a choice, not mental illness, but actual physical differences in brain structure. I found that really interesting.
Yes they are different "physiologically"
Up until a few years ago, males who "wanted to wear dresses" or at least if it got to the medical side were treated with chorionic gonadatropin to make their testes come down.
but some background, for the curious. Most of the males have normal or even high testosterone levels, but even higher conversion to estradiol, which in males is high in late age and protects against cardiovascular events. The gonatropin was stimulating more test. and converted to even higher estradiol. a vicious circle duplicating the menses, cramps, as estradiol is a strong stimulant. females who "wanted to wear comfortable shoes" were ignored. females have higher levels of testosterone but its protein bound typically, in the comfortable shoe category, free testosterone is higher. causing the hair on upper lip, and premature alopecia.
hormones can change genes and "reprogram" the proteins and other stuff in the body, thus the differences in brain structure, body etc.
the main reason for this becoming a major issue in this day and age is because the world is "estrogen toxic"
Many chemicals released in the environment have SARs (structural activity relationships) similar to estrogen and mimic their biophysiological chemistry.
releasing agents in plastics, pvc, etc.
aromatase inhibitors can be used today to block the estrogen in males, but it is usually to late, as the socialoloical behavioral patterns have been ingrained for several years and besides its acceptable.
from the eugenics point of view its a really good solution to over population